My niece and nephew are having hallucination? HELP?

To bad that you don't believe in that stuff. Children see more than we do. I heard hundreds stories from mothers that their kids see some scary people or funny people that make them laugh to tears. They fear them. My friends daughter was screaming every time at night and never slept in the bedroom. Only in the living room. They couldnt stop her it was going on for about 4 months until they moved out, than it stopped. They were living next to a grave yard.